Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
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| electrophoretic and immunological comparisons of chloroplast and prokaryotic ribosomal proteins reveal that certain families of large subunit proteins are evolutionarily conserved. | antibodies to individual chloroplast ribosomal (r-)proteins of chlamydomonas reinhardtii synthesized in either the chloroplast or the cytoplasm were used to examine the relatedness of chlamydomonas r-proteins to r-proteins from the spinach (spinacia oleracea) chloroplast, escherichia coli, and the cyanobacterium anabaena 7120. in addition, 35s-labeled chloroplast r-proteins from large and small subunits of c. reinhardtii were co-electrophoresed on 2-d gels with unlabeled r-proteins from similar ... | 1989 | 2504932 |
| preparation and properties of a cross-linked complex between ferredoxin--nadp+ reductase and flavodoxin. | the electrostatically stabilized complex between anabaena variabilis ferredoxin--nadp+ reductase and azotobacter vinelandii flavodoxin has been covalently cross-linked by treatment with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide. the covalent complex exhibits a molecular mass and fmn/fad content consistent with that expected for a 1:1 stoichiometry of the two flavoproteins. immunochemical cross-reactivity is exhibited by the covalent complex with rabbit antisera prepared separately against ea ... | 1989 | 2506011 |
| occurrence of the hepatotoxic cyanobacterium nodularia spumigena in the baltic sea and structure of the toxin. | water blooms formed by potentially toxic species of cyanobacteria are a common phenomenon in the baltic sea in late summer. twenty-five cyanobacterial bloom samples were collected from open and coastal waters of the baltic sea during 1985 to 1987, and their toxicity was determined by mouse bioassay. all of 5 bloom samples from the southern baltic sea, 6 of 6 from the open northern baltic sea (gulf of finland), and 7 of 14 finnish coastal samples were found to contain hepatotoxic cyanobacteria. n ... | 1989 | 2506812 |
| regulation of expression and nucleotide sequence of the anabaena variabilis reca gene. | the expression of the cyanobacterial reca gene, isolated from anabaena variabilis, has been examined at the levels of transcript and protein abundance. exposure of the cyanobacterium to a variety of dna-damaging agents, including mitomycin c, methyl methanesulfonate, and uv irradiation, results in a rapid increase in the abundance of the reca transcript above basal levels as determined by northern (rna) blot analysis. a concomitant increase in the abundance of a 37- to 38-kilodalton polypeptide ... | 1989 | 2507530 |
| transformation of a filamentous cyanobacterium by electroporation. | the filamentous cyanobacterium anabaena sp. strain m131 was transformed with the shuttle vector prl6 by electroporation. optimum conditions for electroporation required relatively high field strengths with short time constants. restriction significantly lowered the efficiency of transformation. a plasmid containing a single unmodified avaii restriction site transformed cells with about 100-fold-lower efficiency than did the same plasmid with a modified restriction site. | 1989 | 2507531 |
| physical and genetic maps of the genome of the heterocyst-forming cyanobacterium anabaena sp. strain pcc 7120. | a restriction map of the chromosome of the cyanobacterium anabaena sp. strain pcc 7120 was generated by the determination of the order of restriction fragments of the infrequently cleaving restriction endonucleases avrii, sali, and psti. these restriction fragments were resolved by the pulsed homogeneous orthogonal field gel electrophoresis system of pulsed-field gel electrophoresis (i. bancroft and c. p. wolk, nucleic acids res. 16:7405-7418, 1988). other infrequently cutting restriction endonu ... | 1989 | 2509424 |
| determination of anatoxin-a, the neurotoxin of anabaena flos-aquae cyanobacterium, in algae and water by gas chromatography-mass spectrometry. | 1989 | 2512321 | |
| use of degenerate oligonucleotides for amplification of the nifh gene from the marine cyanobacterium trichodesmium thiebautii. | trichodesmium spp. are marine filamentous, nonheterocystous, nitrogen-fixing cyanobacteria which are an important component of marine ecosystems. this organism has never been maintained in axenic culture, and there has remained some doubt as to the identity of the organism responsible for nitrogen fixation in trichodesmium aggregates. by using degenerate oligonucleotide primers, it has been possible to amplify, clone, and sequence a segment of the nifh gene from a natural assemblage of trichodes ... | 1989 | 2513774 |
| evolution of antioxidant mechanisms: thiol-dependent peroxidases and thioltransferase among procaryotes. | glutathione peroxidase and glutathione s-transferase both utilize glutathione (gsh) to destroy organic hydroperoxides, and these enzymes are thought to serve an antioxidant function in mammalian cells by catalyzing the destruction of lipid hydroperoxides. only two groups of procaryotes, the purple bacteria and the cyanobacteria, produce gsh, and we show in the present work that representatives from these two groups (escherichia coli, beneckea alginolytica, rhodospirillum rubrum, chromatium vinos ... | 1989 | 2515292 |
| characteristics of the methylammonium/ammonium transport systems of the nitrogen-fixing cyanobacterium anabaena 7120 (atcc 27893). | nh4(+)-transport in anabaena 7120 was studied using the nh4+ analogue, 14ch3nh3+. at ph 7, two energy-dependent nh4(+)-transport systems were detected in both n2- and no3(-)-grown cells, but none in nh4(+)-grown cells. both transport systems showed a low and a high affinity mode of operation depending on the substrate concentration. one of the transport systems showed km values of 8 microm (vmax = 1 nmole min-1mg-1protein) and 80 microm (vmax = 7 nmole min-1mg-1protein), and was insensitive to l ... | 1989 | 2516834 |
| a new procedure for the analysis and purification of naturally occurring anatoxin-a from the blue-green alga anabaena flos-aquae. | anabaena flos-aquae produces at least two neurotoxins termed anatoxin-a (antx-a) and -a(s) [antx-a(s)]. antx-a is a potent postsynaptic depolarizing neuromuscular blocking agent. its structure is the secondary amine, 2-acetyl-9-azabicyclo[4.2.1]non-2-ene. known isolation and analysis methods have not always given satisfactory results. therefore, an improved procedure was developed for both isolation and analysis of antx-a which involves four steps; extraction, clean-up, separation and determinat ... | 1989 | 2516923 |
| cobalt-induced inhibition of growth in cyanobacteria anabaena doliolum and anacystis nidulans: interaction with sulphur containing amino acids. | cobalt, above 1 microm concentration was growth inhibitory for both a. doliolum and a. nidulans. its toxicity was mitigated by sulphur containing amino acids (cystine and cysteine), however, methionine could not mitigate the cobalt toxicity at all. | 1989 | 2517422 |
| effect of anatoxin-a(s) from anabaena flos-aquae nrc-525-17 on blood pressure, heart rate, respiratory rate, tidal volume, minute volume, and phrenic nerve activity in rats. | the effects of anatoxin-a(s) [antx-a(s)] from the cyanobacterium anabaena flos-aquae nrc-525-17 on mean arterial blood pressure, heart rate, respiratory rate, tidal volume, minute volume, and phrenic nerve activity were evaluated in anesthetized sprague-dawley rats. anatoxin-a(s) was administered by continuous intravenous infusion. the initial effect of the toxin was to slow the heart rate and reduce arterial blood pressure, followed by much more pronounced reductions in these parameters. the ma ... | 1989 | 2517795 |
| toxicity of chromium and tin to anabaena doliolum. interaction with sulphur-containing amino acids and thiols. | toxicity of chromium and tin on growth, heterocyst differentiation, nitrogenase activity and 14co2 uptake of anabaena doliolum and its amelioration by sulphur-containing amino acids and thiols has been studied. the final growth yield was found to be approximately 51% and 58% of control at sublethal concentration of chromium and tin respectively. among various amino acids tested, cysteine (0.05 mm) significantly restored growth, heterocyst differentiation, nitrogenase and 14co2 uptake of test alg ... | 1989 | 2518521 |
| nucleotide sequence of the gene encoding the 33 kda water oxidizing polypeptide in anabaena sp. strain pcc 7120 and its expression in escherichia coli. | the 33 kda extrinsic polypeptide of photosystem ii, also known as the manganese-stabilizing polypeptide (msp), is located on the lumen side of the thylakoid and is involved in water oxidation. the gene for msp, designated woxa, has been cloned from the nitrogen-fixing filamentous cyanobacterium anabaena and sequenced. the woxa open reading frame was found to be 819 bp. the deduced amino acid sequence was 63% and 59% homologous with that of synechococcus and synechocystis, respectively, and 44% c ... | 1989 | 2518833 |
| purification of an acidic plastocyanin from microcystis aeruginosa. | plastocyanin and cytochrome c-553 are two functionally equivalent electron carriers in the photosynthetic chain of cyanobacteria. microcystis aeruginosa, a unicellular cyanobacterium which grows well at a high ph (8.6) and which was not known to possess plastocyanin, has been studied for its ability to synthesize plastocyanin in culture media with and without cu. in the absence of cu, an acidic cytochrome c-553 alone was isolated. with the inclusion of 2 microm cu, cytochrome c-553 synthesis was ... | 1989 | 2537099 |
| concerted two-dimensional nmr approaches to hydrogen-1, carbon-13, and nitrogen-15 resonance assignments in proteins. | when used in concert, one-bond carbon-carbon correlations, one-bond and multiple-bond proton-carbon correlations, and multiple-bond proton-nitrogen correlations, derived from two-dimensional (2d) nmr spectra of isotopically enriched proteins, provide a reliable method of assigning proton, carbon, and nitrogen resonances. in contrast to procedures that simply extend proton assignments to carbon or nitrogen resonances, this technique assigns proton, carbon, and nitrogen resonances coordinately on ... | 1989 | 2539856 |
| calmodulin in heterocystous cyanobacteria: biochemical and immunological evidence. | the occurrence activity and localization of calmodulin in three heterocystous cyanobacteria of the genus anabaena were studied. boiled crude extracts caused a ca2+-dependent stimulation of nad kinase. such a stimulation was blocked by egta and chlorpromazine, sds-page and western blot analysis using antiserum against eukaryotic spinach calmodulin, revealed a polypeptide of about 17 kda. immunogold localization of calmodulin gave a dense gold label in both vegetative cells and heterocysts. the la ... | 1989 | 2551772 |
| tn5 mutagenesis of anabaena sp. strain pcc 7120: isolation of a new mutant unable to grow without combined nitrogen. | methylation by ava methylases in escherichia coli increases the efficiency to transfer of tn5 in pbr322bla:: tn5 from e. coli to anabaena sp. strain pcc 7120 by conjugation. following conjugation, tn5 but not pbr322 sequences were found at many different positions in the anabaena chromosome. this procedure was used to mutagenize, tag, and clone a previously unrecognized gene required for nitrogen fixation in this anabaena sp. | 1989 | 2551892 |
| characterization of an insertion sequence (is891) of novel structure from the cyanobacterium anabaena sp. strain m-131. | when recombinant plasmids that were transferred to the cyanobacterium anabaena sp. strain m-131 were transferred back to escherichia coli, some of the transformants contained inserts. one of the insertion sequences (iss) was characterized by sequencing. this 1,351-base-pair is contained an open reading frame that was capable of encoding a peptide of 310 amino acids and had terminal sequences with distinctive structures, but it lacked terminal inverted repeats and did not duplicate target dna upo ... | 1989 | 2553665 |
| nitrogen fixation (nif) genes of the cyanobacterium anabaena species strain pcc 7120. the nifb-fdxn-nifs-nifu operon. | a second nitrogen fixation (nif) operon in the cyanobacterium (blue-green alga) anabaena (nostoc) sp. strain pcc 7120 has been identified and sequenced. it is located just upstream of the nifhdk operon and consists of four genes in the order nifb, fdxn, nifs, and nifu. the three nif genes were identified on the basis of their similarity with the corresponding genes from other diazotrophs. the fourth gene, fdxn, codes for a bacterial type ferredoxin (mulligan, m. e., buikema, w. j., and haselkorn ... | 1989 | 2553733 |
| purification and properties of glutamine synthetase from the non-n2-fixing cyanobacterium phormidium laminosum. | soluble glutamine synthetase activity (l-glutamate:ammonia ligase, adp forming, ec 6.3.1.2) was purified to electrophoretic homogeneity from the filamentous non-n2-fixing cyanobacterium phormidium laminosum (oh-1-p.cl1) by using conventional purification procedures in the absence of stabilizing ligands. the pure enzyme showed a specific activity of 152 mumol of gamma-glutamylhydroxamate formed.min-1 (transferase activity), which corresponded to 4.4 mumol of pi released.min-1 (biosynthetic activi ... | 1989 | 2563365 |
| impact of chromium and tin on a nitrogen-fixing cyanobacterium anabaena doliolum: interaction with bivalent cations. | the toxicity of chromium and tin on growth, uptake of no3- and nh4+, nitrate reductase and glutamine synthetase activity of anabaena doliolum, and its interaction with bivalent cations, viz. ca2+, mg2+, mn2+, ni2+, co2+, and zn2+, has been studied. some interacting cations, viz. ca, mg, and mn, substantially antagonized the toxic effects of chromium and tin with reference to growth and nutrient (no3- and nh4+) uptake in the hierarchical sequence ca greater than mg greater than mn, whereas the se ... | 1989 | 2565805 |
| comparison of dna restriction fragment length polymorphisms of nostoc strains in and from cycads. | dna was prepared from cyanobacteria freshly isolated from coralloid roots of natural populations of five cycad species: ceratozamia mexicana mexicana (mexico), c. mexicana robusta (mexico), dioon spinulosum (mexico), zamia furfuraceae (mexico) and z. skinneri (costa rica). using the southern blot technique and cloned anabaena pcc 7120 nifk and glna genes as probes, restriction fragment length polymorphisms of these cyanobacterial symbionts were compared. the five cyanobacterial preparations show ... | 1989 | 2569858 |
| protective effects of certain natural and synthetic complexans on the toxicity of chromium and tin to a n2-fixing cyanobacterium, anabaena doliolum. | the effects of chromium and tin on survival, growth, carbon fixation, nitrate reduction, ammonia assimilation, and nitrogenase activity of a n2-fixing cyanobacterium. anabaena doliolum, and their amelioration by synthetic and natural complexans, viz., edta, nitrilotriacetic acid (nta), pyridine dicarboxylic acid (pda), and citrate, have been studied. chromium proved to be much more toxic than tin, as it inhibited growth yield (49%), carbon fixation (53%), and nitrate reductase (79%), glutamine s ... | 1989 | 2575394 |
| attachment of toxigenic vibrio cholerae 01 to various freshwater plants and survival with a filamentous green alga, rhizoclonium fontanum. | in bangladesh, cholera epidemics occur twice a year. v. cholerae 01 are readily isolated from the environment only during epidemics. the interepidemic reservoirs or sites of survival and multiplication of v. cholerae are still unknown. investigations were carried out with various fresh-water plants as possible reservoirs of v. cholerae in the environment. attachment to and acute population changes of v. cholerae on various plant surfaces was used as a screening technique to screen a particular p ... | 1989 | 2607573 |
| the plastid rpoa gene encoding a protein homologous to the bacterial rna polymerase alpha subunit is expressed in pea chloroplasts. | the gene rpoa, encoding a protein homologous to the alpha subunit of rna polymerase from escherichia coli has been located in pea chloroplast dna downstream of the petd gene for subunit iv of the cytochrome b-f complex. nucleotide sequence analysis has revealed that rpoa encodes a polypeptide of 334 amino acid residues with a molecular weight of 38916. northern blot analysis has shown that rpoa is co-transcribed with the gene for ribosomal protein s11. a lacz-rpoa gene-fusion has been constructe ... | 1989 | 2671652 |
| regional brain cholinesterase activity in rats injected intraperitoneally with anatoxin-a(s) or paraoxon. | adult male long-evans rats were injected intraperitoneally with 1.5, 3.0 or 9.0 micrograms/kg of anatoxin-a(s) that had been extracted from laboratory-grown anabaena flos-aquae nrc-525-17, 800 micrograms/kg of paraoxon, or a control solution. blood, anterior spinal cord, and brain cerebellar, cortical, medullary, midbrain, hippocampal, hypothalamic, olfactory and striatal cholinesterase activity was determined in rats that died prior to 2 hours or were anesthetized and killed at 2 hours. unlike ... | 1989 | 2815113 |
| nitrogen-fixing cyanobacterium with a high phycoerythrin content. | the elemental and molecular composition, pigment content, and productivity of a phycoerythrin-rich nitrogen-fixing cyanobacterium-an anabaena strain isolated from the coastal lagoon albufera de valencia, spain-has been investigated. when compared with other heterocystous species, this strain exhibits similar chlorophyll a, carotene, and total phycobiliprotein contents but differs remarkably in the relative proportion of specific phycobiliproteins; the content of c-phycoerythrin amounts to 8.3% ( ... | 1989 | 16347884 |
| enhancement of cyanobacterial salt tolerance by combined nitrogen. | presence of certain nitrogenous compounds in the growth medium significantly enhanced the salt tolerance of the fresh-water cyanobacterium anabaena sp. strain l-31 as well as the brackish water cyanobacterium anabaena torulosa. among these, nitrate, ammonium, and glutamine were most effective followed by glutamate and aspartate. these nitrogenous compounds also inhibited na(+) influx in both anabaena spp. with the same order of effectiveness as that observed for protection against salt stress. t ... | 1989 | 16666516 |
| ethoxyzolamide inhibition of co(2)-dependent photosynthesis in the cyanobacterium synechococcus pcc7942. | cells of the cyanobacterium, synechococcus pcc7942, grown under high inorganic carbon (c(i)) conditions (1% co(2); ph 8) were found to be photosynthetically dependent on exogenous co(2). this was judged by the fact that they had a similar photosynthetic affinity for co(2) (k(0.5)[co(2)] of 3.4-5.4 micromolar) over the ph range 7 to 9 and that the low photosynthetic affinity for c(i) measured in dense cell suspensions was improved by the addition of exogenous carbonic anhydrase (ca). the ca inhib ... | 1989 | 16666544 |
| reexamination of the three-dimensional structure of the small subunit of rubisco from higher plants. | the structure of l(8)s(8) rubisco (where l is the large subunit and s is the small subunit) from spinach has been determined to a resolution of 2.8 ångstrom by using fourfold averaging of an isomorphous electron density map based on three heavy-atom derivatives. the structure of the s subunit is different from that previously reported for the tobacco s subunit in spite of 75 percent sequence identity. the elements of secondary structure, four antiparallel beta strands and two alpha helices, are ... | 1989 | 17740342 |
| saskatchewan. blue green algae (anabaena sp.) poisoning in cattle. | 1989 | 17423446 | |
| ca requirement for aerobic nitrogen fixation by heterocystous blue-green algae. | the requirement of ca(2+) for growth and nitrogen fixation has been investigated in two strains of heterocystous blue-green algae (anabaena sp. and anabaena atcc 33047). with combined nitrogen (nitrate or ammonium) or with n(2) under microaerobic conditions, ca(2+) was not required for growth, at least in concentrations greater than traces. in contrast, ca(2+) was required as a macronutrient for growth and nitrogen fixation with air as the nitrogen source. addition of ca(2+) to an aerobic cultur ... | 1990 | 16667401 |
| effect of boron deficiency on photosynthesis and reductant sources and their relationship with nitrogenase activity in anabaena pcc 7119. | nitrogenase activity of anabaena pcc 7119 is inhibited under conditions of boron deficiency. to elucidate the mechanisms of this inhibition, this study examined how the deficiency of boron affected photosynthesis, photosynthetic pigments, the enzymes of the oxidative pentose phosphate pathway, and respiration of anabaena pcc 7119 cultures. after 24 to 48 hours of boron deficiency, reductions in photosynthetic o(2) evolution and in co(2) fixation were observed. at the same time, the activities of ... | 1990 | 16667503 |
| effects of co(2) concentration during growth on fatty acid composition in microalgae. | the degree of unsaturation of fatty acids was higher in chlorella vulgaris 11h cells grown with air (low-co(2) cells) than in the cells grown with air enriched with 2% co(2) (high-co(2) cells). the change in the ratio of linoleic acid to alpha-linolenic acid was particularly significant. this change of the ratio was observed in four major lipids (monogalactosyldiacylglycerol, digalactosyldiacylglycerol, phosphatidylcholine, and phosphatidylethanolamine). the relative contents of lipid classes we ... | 1990 | 16667592 |
| dna probes show genetic variation in cyanobacterial symbionts of the azolla fern and a closer relationship to free-living nostoc strains than to free-living anabaena strains. | twenty-two isolates of anabaena azollae derived from seven azolla species from various geographic and ecological sources were characterized by dna-dna hybridization. cloned dna fragments derived from the genomic sequences of three different a. azollae isolates were used to detect restriction fragment length polymorphism among all symbiotic anabaenas. dna clones were radiolabeled and hybridized against southern blot transfers of genomic dnas of different isolates of a. azollae digested with restr ... | 1990 | 16348182 |
| ammonium excretion by an l-methionine-dl-sulfoximine-resistant mutant of the rice field cyanobacterium anabaena siamensis. | an ammonium-excreting mutant (ss1) of the rice field nitrogen-fixing cyanobacterium anabaena siamensis was isolated after ethyl methanesulfonate mutagenesis by selection on 500 mum l-methionine-dl-sulfoximine. ss1 grew in the presence and absence of (l)-methionine-dl-sulfoximine at a rate comparable to that of the wild-type strain, with a doubling time of 5.6 h. the rate of ammonium release by ss1 depended on cell density; it peaked at the 12th hour of growth with 8.7 mumol mg of chlorophyll h ( ... | 1990 | 16348353 |
| arginyl groups involved in the binding of anabaena ferredoxin--nadp+ reductase to nadp+ and to ferredoxin. | chemical modification of ferredoxin--nadp+ reductase from the cyanobacteria anabaena has been performed using the alpha-dicarbonyl reagent phenylglyoxal. inactivation of both the diaphorase and cytochrome-c reductase activities, characteristic of the enzyme, indicates the involvement of one or more arginyl residues in the catalytic process of the enzyme. the determination of the rate constants for the inactivation process under different conditions, including those in which substrates, nadp+ and ... | 1990 | 2105214 |
| modification of dinitrogenase reductase in the cyanobacterium anabaena variabilis due to c starvation and ammonia. | in the heterocystous cyanobacterium anabaena variabilis, a change in nitrogenase activity and concomitant modification of dinitrogenase reductase (the fe protein of nitrogenase) was induced either by nh4cl at ph 10 (s. reich and p. böger, fems microbiol. lett. 58:81-86, 1989) or by cessation of c supply resulting from darkness, co2 limitation, or inhibition of photosystem ii activity. modification induced by both c limitation and nh4cl was efficiently prevented by anaerobic conditions. under air ... | 1990 | 2105302 |
| transport of basic amino acids by the dinitrogen-fixing cyanobacterium anabaena pcc 7120. | two transport systems for l-arginine were evident in anabaena sp. strain pcc 7120: a high-affinity one (km, 1.7 microm) that accumulated arginine within the cells through an energy-requiring process and another one that exhibited low affinity for l-arginine (km, 0.75 mm) and was unable to accumulate the substrate. both systems were inhibited by l-canavanine, l-lysine, and l-ornithine. two systems were also evident for l-lysine uptake (km, 1.9 and 110 microm, respectively). after selection for re ... | 1990 | 2105956 |
| effects of petroleum oils and their paraffinic, asphaltic, and aromatic fractions on photosynthesis and respiration of microalgae. | inhibition of photosynthesis was more severe than that of respiration in anabaena doliolum exposed to assam crude oil, furnace oil, petrol, diesel, and kerosene. variabilities in toxicity of these oils, which seem to be related to their aromatic and asphaltic contents, were observed. diesel and furnace oil, due to greater concentrations of aromatics, were more toxic than other oils. the toxic effects of asphaltic fractions were similar to those of aromatics. the study showed that the effects of ... | 1990 | 2107072 |
| long-term persistence of toxigenic vibrio cholerae 01 in the mucilaginous sheath of a blue-green alga, anabaena variabilis. | cholera epidemics occur twice a year in the endemic area of bangladesh. vibrio cholerae 01 can be isolated from the environment only during the epidemics and the question of possible interepidemic environmental reservoirs of v. cholerae remains open. the present laboratory-based studies investigate the role of an aquatic alga, anabaena variabilis, as a possible reservoir. persistence of v. cholerae inside the mucilaginous sheath of a. variabilis was observed by phase-contrast and fluorescent mic ... | 1990 | 2109096 |
| growth, photosynthesis and nitrogen fixation of anabaena doliolum exposed to assam crude extract. | 1990 | 2109645 | |
| control of nitrogenase recovery from oxygen inactivation by ammonia in the cyanobacterium anabaena sp. strain ca (atcc 33047). | the control of nitrogenase recovery from inactivation by oxygen was studied in anabaena sp. strain ca (atcc 33047). nitrogenase activity (acetylene reduction) in cultures grown in 1% co2 in air was inhibited by exposure to 1% co2-99% o2 and allowed to recover in the presence of high oxygen tensions. cultures exposed to hyperbaric levels of oxygen in the presence of 10 mm nh4no3 were incapable of regaining nitrogenase activity, whereas control cultures returned to 65 to 80% of their original acti ... | 1990 | 2110151 |
| identification and characterization of heta, a gene that acts early in the process of morphological differentiation of heterocysts. | envelope polysaccharide is a major early diagnostic of differentiating heterocysts. the mutation in mutant ef116 of anabaena sp. strain pcc 7120 reduces the cohesiveness of this polysaccharide. a 3.5-kilobase fragment of dna cloned from the wild type of this anabaena sp. was previously shown to complement this mutation. we present the nucleotide sequence of a 2,555-base-pair portion of this fragment containing an open reading frame (orf) of 601 amino acids. complementation analysis using deletio ... | 1990 | 2111805 |
| redox and spectral properties of flavodoxin from anabaena 7120. | we report here on the spectrophotometric and electrochemical properties of the flavodoxin from anabaena 7120 and compare these properties with those of flavodoxins that have been studied previously. molar absorption coefficients have been determined for all three oxidation states of this protein, at various wavelengths. for oxidized flavodoxin, molar absorption coefficients for the absorption maxima at 464 and 373 nm were 9200 and 8500 m-1 cm-1, respectively. reduction by the first electron prod ... | 1990 | 2112901 |
| [the surface membrane charge of bacteria and its role in serine proteinase secretion by bacillus subtilis cells]. | univalent, bivalent and trivalent metal cations increase the fluorescence yield of 9-aminoacridine in the suspensions of chromatophores of the purple nonsulfur bacterium rhodospirillum rubrum isolated thylakoid membranes and cells of cyanobacterium anabaena variabilis, cells bacillus subtilis. the active cation concentrations increase about in 10 times with the decrease of their valency by one. it points to the fact that the changes in 9-aminoacridine fluorescence serve for the monitoring of the ... | 1990 | 2112959 |
| expression of the anabaena sp. strain pcc 7120 xisa gene from a heterologous promoter results in excision of the nifd element. | an 11-kilobase-pair element interrupts the nifd gene in vegetative cells of anabaena sp. strain pcc 7120. the nifd element normally excises only from the chromosomes of cells that differentiate into nitrogen-fixing heterocysts. the xisa gene contained within the element is required for the excision. shuttle vectors containing the escherichia coli tac consensus promoter fused to various 5' deletions of the xisa gene were constructed and conjugated into anabaena sp. strain pcc 7120 cells. some of ... | 1990 | 2113913 |
| expression, nucleotide sequence and mutational analysis of two open reading frames in the nif gene region of anabaena sp. strain pcc7120. | a 1.8 kb transcript corresponding to a region of the anabaena 7120 chromosome 4 kb downstream of the nifhdk operon appears 12-18 h after heterocyst induction. the dna corresponding to this transcript was sequenced and found to contain two open reading frames, designated orf 1 and orf 2. two polypeptides, of 30 kda and 13 kda, encoded by these orfs were expressed in escherichia coli. an apparent start site for the transcript, detected by s1 nuclease protection, was located 42 bp upstream of the a ... | 1990 | 2115111 |
| residues in three conserved regions of the small subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase are required for quaternary structure. | to explore the role of individual residues in the small subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase (ec 4.1.1.39), small subunits with single amino acid substitutions in three regions of relative sequence conservation were produced by directed mutagenesis of the rbcs gene from anabaena 7120. these altered small subunits were cosynthesized with large subunits (from an expressed anabaena rbcl gene) in escherichia coli. mutants were analyzed for effects on quaternary structure and ca ... | 1990 | 2116005 |
| comparison of the kinetics of reduction and intramolecular electron transfer in electrostatic and covalent complexes of ferredoxin-nadp+ reductase and flavodoxin from anabaena pcc 7119. | the kinetics of reduction and intracomplex electron transfer in electrostatically stabilized and covalently crosslinked complexes between ferredoxin-nadp+ reductase (fnr) and flavodoxin (fld) from the cyanobacterium anabaena pcc 7119 were compared using laser flash photolysis. the second-order rate constant for reduction by 5-deazariboflavin semiquinone (drfh) of fnr within the electrostatically stabilized complex at 10 mm ionic strength (4.0 x 10(8) m-1 s-1) was identical to that for free fnr. ... | 1990 | 2116771 |
| a morphometric and x-ray energy dispersive approach to monitoring ph-altered cadmium toxicity in anabaena flos-aquae. | cadmium toxicity and uptake as influenced by different ph values have been studied in the freshwater cyanobacterium anabaena flos-aquae, using the techniques of morphometric analysis, x-ray energy dispersive analysis and atomic absorption spectrophotometry. a general reduction in cell dimension, thylakoid surface area, number and volume of polyhedral bodies, polyphosphate bodies, cyanophycin granules, lipid bodies, membrane limited crystalline inclusions, volume and number of wall layers and mes ... | 1990 | 2117425 |
| the toxicity and bioaccumulation of selenate, selenite and seleno-l-methionine in the cyanobacterium anabaena flos-aquae. | a laboratory investigation was conducted to study the toxicity and bioaccumulation of seleno-l-methionine, selenate and selenite in the cyanobacterium anabaena flos-aquae. the first sub-lethal effects of seleno-l-methionine, selenite and selenate occurred at 0.1, 3.0, and 3.0 mg/l, respectively with a decrease in chlorophyll a concentration (p less than 0.0001). selenium bioconcentration factors (bcf) were in the order of seleno-l-methionine, selenite, and selenate. significant decreases in intr ... | 1990 | 2117426 |
| a sequence-specific dna-binding factor (vf1) from anabaena sp. strain pcc 7120 vegetative cells binds to three adjacent sites in the xisa upstream region. | a dna-binding factor (vf1) partially purified from anabaena sp. strain pcc 7120 vegetative cell extracts by heparin-sepharose chromatography was found to have affinity for the xisa upstream region. the xisa gene is required for excision of an 11-kilobase element from the nifd gene during heterocyst differentiation. previous studies of the xisa upstream sequences demonstrated that deletion of this region is required for the expression of xisa from heterologous promoters in vegetative cells. mobil ... | 1990 | 2118506 |
| structural and chemical properties of a flavodoxin from anabaena pcc 7119. | structural and chemical properties of a flavodoxin from anabaena pcc 7119 are described. the first 36 residues of the amino-terminal amino acid sequence have been determined and show extensive homology with flavodoxins isolated from other sources. anabaena flavodoxin exhibits a net negative change (-3) in the helix-1 segment as found with other cyanobacterial flavodoxins synechococcus 6301 (anacystis nidulans) and nostoc mac, but in contrast to the net positive charge found in this region in the ... | 1990 | 2119231 |
| developmental regulation and spatial pattern of expression of the structural genes for nitrogenase in the cyanobacterium anabaena. | depriving the cyanobacterium anabaena of fixed nitrogen induces the differentiation of heterocysts at intervals along its filaments. to test whether the oxygen-deficient conditions believed to prevail within mature heterocysts are sufficient, in the absence of fixed nitrogen, to elicit the expression of nitrogenase, pnifhdk was fused transcriptionally to luxab (encoding luciferase). expression, monitored from individual cells as light emission, was localized (with a resolution of approximately 1 ... | 1990 | 2120040 |
| adenylate cyclase activity in cyanobacteria: activation by ca(2+)-calmodulin and a calmodulin-like activity. | an adenylate cyclase activity was partially characterized in the cyanobacterium anabaena sp. the enzyme activity is found in soluble cell fractions and shows an apparent molecular weight of about 183,400. this adenylate cyclase is activated by ca2+ and bovine brain or spinach calmodulin and it is inhibited by egta and some phenothiazine derivatives. furthermore, anabaena sp. extracts contain a calmodulin-like activity which stimulates bovine brain cyclic amp phosphodiesterase and the anabaena ad ... | 1990 | 2121284 |
| immunologically cross-reactive and redox-competent cytochrome b6/f-complexes in the chlorophyll-free plasma membrane of cyanobacteria. | plasma and thylakoid membranes were separated and purified from cell-free extracts of the cyanobacteria anacystis nidulans, synechocystis 6714, anabaena variabilis and nostoc sp. strain mac. immunoblots of the membrane proteins using antisera raised against subunits i-iv of the chloroplast b6/f-complex gave evidence for the presence of a homologous complex in both plasma and thylakoid membranes from the four species of cyanobacteria investigated. both plasma and thylakoid membranes catalyzed the ... | 1990 | 2121543 |
| purification and characterization of acyl carrier protein from two cyanobacteria species. | the acyl carrier protein (acp), an essential protein cofactor for fatty acid synthesis, has been isolated from two cyanobacteria: the filamentous, heterocystous, anabaena variabilis (atcc 29211) and the unicellular synechocystis 6803 (atcc 27184). both acps have been purified to homogeneity utilizing a three-column procedure. synechocystis 6803 acp was purified 1800-fold with 67% yield, while a. variabilis acp was purified 1040-fold with 50% yield. yields of 13.0 micrograms acp/g synechocystis 6 ... | 1990 | 2123456 |
| developmental rearrangement of cyanobacterial nif genes: nucleotide sequence, open reading frames, and cytochrome p-450 homology of the anabaena sp. strain pcc 7120 nifd element. | an 11-kbp dna element of unknown function interrupts the nifd gene in vegetative cells of anabaena sp. strain pcc 7120. in developing heterocysts the nifd element excises from the chromosome via site-specific recombination between short repeat sequences that flank the element. the nucleotide sequence of the nifh-proximal half of the element was determined to elucidate the genetic potential of the element. four open reading frames with the same relative orientation as the nifd element-encoded xis ... | 1990 | 2123860 |
| sequence of the ferredoxin-nadp(+)-reductase gene from anabaena pcc 7119. | 1990 | 2124680 | |
| hydrogen-1, carbon-13, and nitrogen-15 nmr spectroscopy of anabaena 7120 flavodoxin: assignment of beta-sheet and flavin binding site resonances and analysis of protein-flavin interactions. | sequence-specific 1h and 13c nmr assignments have been made for residues that form the five-stranded parallel beta-sheet and the flavin mononucleotide (fmn) binding site of oxidized anabaena 7120 flavodoxin. interstrand nuclear overhauser enhancements (noes) indicate that the beta-sheet arrangement is similar to that observed in the crystal structure of the 70% homologous long-chain flavodoxin from anacystis nidulans [smith et al. (1983) j. mol. biol. 165, 737-755]. a total of 62 noes were ident ... | 1990 | 2125478 |
| bacterial origin of a chloroplast intron: conserved self-splicing group i introns in cyanobacteria. | a self-splicing group i intron has been found in the gene for a leucine transfer rna in two species of anabaena, a filamentous nitrogen-fixing cyanobacterium. the intron is similar to one that is found at the identical position in the same transfer rna gene of chloroplasts of land plants. because cyanobacteria were the progenitors of chloroplasts, it is likely that group i introns predated the endosymbiotic association of these eubacteria with eukaryotic cells. | 1990 | 2125747 |
| heavy metal toxicity in a n2-fixing cyanobacterium, anabaena doliolum: regulation of toxicity by certain environmental factors. | the toxic effects of chromium and tin salts on growth, 14c uptake, heterocyst differentiation, and nitrate reductase, nitrogenase, and glutamine synthetase activities of anabaena doliolum and their regulation by ph, salinity, extracellular metabolites (spent), and organic acids have been studied. the toxicity of the test metals was lowered at alkaline ph and increased at acidic ph. nacl at 20 mm was found to decrease metal toxicity. extracellular metabolites (spent) in a 1:1 ratio (v/v) with fre ... | 1990 | 2129192 |
| characterization of a four-member psba gene family from the cyanobacterium anabaena pcc 7120. | the cyanobacterium anabaena pcc 7120 contains a multigene family that encodes the d1 polypeptide of photosystem ii. this family consists of four members denoted psbai-iv that are each unique but highly homologous. psbaii, iii and iv are more closely related to each other than to psbai. these three copies encode identical polypeptides that differ from the psbai product by 21 amino acids. the transcription initiation site for psbai has been mapped to 64-65 nucleotides upstream from the coding regi ... | 1990 | 2129283 |
| copper-induced expression, cloning, and regulatory studies of the plastocyanin gene from the cyanobacterium synechocystis sp. pcc 6803. | plastocyanin can be detected in synechocystis sp. pcc 6803 when 3 microm copper is added to the growth medium, bg-11. the plastocyanin gene (pete) was cloned from a genomic lambda embl 3 library by screening with the pete gene from anabaena sp. pcc 7937. the synechocystis 6803 pete gene is present as a single copy and, as deduced from the dna sequence, encodes a precursor protein of 126 amino acids. the predicted 29 amino acid transit peptide shows substantial homology to the anabaena 7937 trans ... | 1990 | 2129338 |
| cloning of salinity stress-induced genes from the salt-tolerant nitrogen-fixing cyanobacterium anabaena torulosa. | a subtractive hybridization procedure was used to clone genes of the cyanobacterium anabaena torulosa expressed in response to salt stress. the method uses total rna from salt-treated cells, labeled in vitro, as the probe. hybridization to restriction digests of total dna was used for interspecies comparison; the procedure was also successful for isolation of cosmids by colony hybridization, semiquantitative dot blots, and cosmid characterization by southern blotting. analysis of eleven independ ... | 1990 | 2129399 |
| soluble hydrogenase of anabaena cylindrica. cloning and sequencing of a potential gene encoding the tritium exchange subunit. | a gene potentially encoding a subunit of the soluble hydrogenase of anabaena cylindrica was isolated from a genomic library by screening with a set of redundant oligonucleotides, the sequence of which was deduced from the amino acid sequence of the purified hydrogenase subunit that catalyses tritium exchange. the nucleotide sequence of the potential gene was determined from two overlapping dna fragments spanning 7237 bp of the a. cylindrica genome. the region sequenced contained an open reading ... | 1990 | 2129525 |
| 1h, 13c, and 15n resonance assignments for a ferrocytochrome c553 heme by multinuclear nmr spectroscopy. | a novel strategy has been used to assign the 1h, 13c, and 15n resonances of the heme in anabaena 7120 ferrocytochrome c553. 13c[13c] double-quantum coherence spectroscopy was used to delineate the heme carbons, 1h[13c] single-bond correlation spectroscopy was used to define the attached protons, and 1h[15n] multiple-bond correlation spectroscopy was used to assign the nitrogens. 1h[13c] multiple-bond correlation spectroscopy confirmed many of the assignments. proteins were labeled uniformly with ... | 1990 | 2154947 |
| use of a conditionally lethal gene in anabaena sp. strain pcc 7120 to select for double recombinants and to entrap insertion sequences. | use of the sacb gene (j. l. ried and a. collmer, gene 57:239-246, 1987) provides a simple, effective, positive selection for double recombinants in anabaena sp. strain pcc 7120, a filamentous cyanobacterium. this gene, which encodes the secretory levansucrase of bacillus subtilis, was inserted into the vector portion of a suicide plasmid bearing a mutant version of a chromosomal gene. cells of colonies in which such a plasmid had integrated into the anabaena chromosome through single recombinati ... | 1990 | 2160938 |
| purification, characterization, and complete amino acid sequence of a thioredoxin from a green alga, chlamydomonas reinhardtii. | two thioredoxins (named ch1 and ch2 in reference to their elution pattern on an anion-exchange column) have been purified to homogeneity from the green alga, chlamydomonas reinhardtii. in this paper, we described the properties and the sequence of the most abundant form, ch2. its activity in various enzymatic assays has been compared with those of escherichia coli and spinach thioredoxins. c. reinhardtii thioredoxin ch2 can serve as a substrate for e. coli thioredoxin reductase with a lower effi ... | 1990 | 2191628 |
| cloning, sequencing, and transcriptional analysis of the reca gene of pseudomonas cepacia. | a recombinant plasmid carrying the reca gene of pseudomonas cepacia complements a reca mutation of escherichia coli and restores uv and methylmethane sulfonate resistance, as well as recombinational proficiency. the predicted amino acid (aa) sequence of p. cepacia reca (347 aa; mr, 37256) is highly homologous to the reca proteins from thiobacillus ferrooxidans (74% aa homology), pseudomonas aeruginosa (72%), e. coli (71%), anabaena variabilis (61%), and synechococcus sp. strains pcc7002 (59%). t ... | 1990 | 2227456 |
| nucleotide sequence and expression of a deep-sea ribulose-1,5-bisphosphate carboxylase gene cloned from a chemoautotrophic bacterial endosymbiont. | the gene coding for ribulose-1,5-bisphosphate carboxylase [rubisco; 3-phospho-d-glycerate carboxy-lyase (dimerizing), ec 4.1.1.39] was cloned from a sulfur-oxidizing chemoautotrophic bacterium that resides as an endosymbiont within the gill tissues of alvinoconcha hessleri, a gastropod inhabiting deep-sea hydrothermal vents. nucleotide sequence analysis of the cloned fragment demonstrated that the genes encoding the large (rbcl) and small (rbcs) subunits of the symbiont rubisco were organized si ... | 1990 | 2247456 |
| pathophysiologic effects of anatoxin-a(s) in anaesthetized rats: the influence of atropine and artificial respiration. | the pathophysiologic effects of anatoxin-a(s) from the cyanobacterium anabaena flos-aquae nrc-525-17 were investigated in anaesthetized adult male sprague dawley rats given the toxin by continuous intravenous infusion until death. rats (n = 6) pretreated with atropine sulfate (50 mg/kg) intraperitoneally survived significantly longer (p less than 0.05) than non-atropinized rats (n = 6), suggesting that the muscarinic effects of anatoxin-a(s) were important in the lethal syndrome. in contrast to ... | 1990 | 2255668 |
| detection and characterization of hyperfine-shifted resonances in the proton nuclear magnetic resonance spectrum of anabaena 7120 ferredoxin at high magnetic fields. | this paper presents previously unobserved signals in the 1h nmr spectra of oxidized and reduced [2fe-2s]-ferredoxin from anabaena 7120 detected at 400, 500, and 600 mhz. the signals shifted to low field exhibited longitudinal relaxation (t1) values in the range of 100-400 microseconds and line widths in the range of 1-10 khz (at 400 mhz), and the chemical shifts of all signals showed strong temperature dependence. although the line widths were smaller at lower magnetic fields, the resolution was ... | 1990 | 2327800 |
| multinuclear magnetic resonance studies of the 2fe.2s* ferredoxin from anabaena species strain pcc 7120. 1. sequence-specific hydrogen-1 resonance assignments and secondary structure in solution of the oxidized form. | complete sequence-specific assignments were determined for the diamagnetic 1h resonances from anabaena 7120 ferredoxin (mr = 11,000). a novel assignment procedure was followed whose first step was the identification of the 13c spin systems of the amino acids by a 13c(13c) double quantum correlation experiment [oh, b.-h., westler, m. w., darba, p., & markley, j. l. (1988) science 240, 908-911]. then, the 1h spin systems of the amino acids were identified from the 13c spin systems by means of dire ... | 1990 | 2354171 |
| multinuclear magnetic resonance studies of the 2fe.2s* ferredoxin from anabaena species strain pcc 7120. 2. sequence-specific carbon-13 and nitrogen-15 resonance assignments of the oxidized form. | multinuclear two-dimensional nmr techniques were used to assign nearly all diamagnetic 13c and 15n resonances of the plant-type 2fe.2s* ferredoxin from anabaena sp. strain pcc 7120. since a 13c spin system directed strategy had been used to identify the 1h spin systems [oh, b.-h., westler, w. m., & markley, j. l. (1989) j. am. chem. soc. 111, 3083-3085], the sequence-specific 1h assignments [oh, b.-h., & markley, j. l. (1990) biochemistry (first paper of three in this issue)] also provided seque ... | 1990 | 2354172 |
| multinuclear magnetic resonance studies of the 2fe.2s* ferredoxin from anabaena species strain pcc 7120. 3. detection and characterization of hyperfine-shifted nitrogen-15 and hydrogen-1 resonances of the oxidized form. | all the nitrogen signals from the amino acid side chains and 80 of the total of 98 backbone nitrogen signals of the oxidized form of the 2fe.2s* ferredoxin from anabaena sp. strain pcc 7120 were assigned by means of a series of heteronuclear two-dimensional experiments [oh, b.-h. mooberry, e. s., & markley, j. l. (1990) biochemistry (second paper of three in this issue )]. two additional nitrogen signals were observed in the one-dimensional 15n nmr spectrum and classified as backbone amide reson ... | 1990 | 2354173 |
| biosynthesis of the tropane-related cyanobacterial toxin anatoxin-a: role of ornithine decarboxylase. | a study was made of the biosynthesis by anabaena flos-aquae of the tropane-related alkaloid anatoxin-a. evidence is presented that the toxin arises from ornithine via putrescine (1,4-diaminobutane) and that ornithine decarboxylase (ec 4.1.1.17) is involved. an ornithine decarboxylase preparation, with optimal activity at ph 8, was obtained from anabaena flos-aquae and partially purified by gel-filtration chromatography on deae-cellulose. one major and one minor peak of enzymic activity were obta ... | 1990 | 1367427 |
| genomic integration system based on pbr322 sequences for the cyanobacterium synechococcus sp. pcc7942: transfer of genes encoding plastocyanin and ferredoxin. | synechococcus sp. pcc7942 recipient strains were constructed for the chromosomal integration of dna fragments cloned in any pbr322-derived vector, which carries the ampicillin resistance (apr) marker. the construction was based on the incorporation of specific recombination targets, the so-called 'integration platforms', into the chromosomal metf gene. these platforms consist of an incomplete bla gene (aps) and the pbr322 ori separated from each other by a gene encoding an antibiotic (streptomyc ... | 1990 | 1701408 |
| isolation and overexpression in escherichia coli of the flavodoxin gene from anabaena pcc 7119. | the gene coding for flavodoxin from anabaena pcc 7119 was cloned by using the polymerase chain reaction (pcr). the gene is transcribed into a 1250-base transcript. the expression of the flavodoxin gene was analysed and found to be regulated at the transcriptional level by the availability of iron. the pcr-amplified gene was cloned into the expression vector ptrc 99b and expressed in escherichia coli. high concentrations of flavodoxin were found (20% of total protein). the recombinant protein was ... | 1991 | 1720613 |
| a small multigene family encodes the rod-core linker polypeptides of anabaena sp. pcc7120 phycobilisomes. | the cpc operon of anabaena sp. pcc7120 is shown to encode ten genes: 5'-cpcb-cpca-cpcc-cpcd-cpce-cpcf- cpcg1-cpcg2-cpcg3-cpcg4-3'. the 3' portion of this operon includes four tandemly repeated genes encoding phycocyanin (pc)-associated, rod-core linker polypeptides of the phycobilisomes (pbs). the products of these four genes are most similar at their n termini, and overall are 50-61% identical and 68-76% similar to one another. the four cpcg proteins of anabaena sp. pcc7120 are 41-47% identical ... | 1991 | 1743523 |
| oxidation-reduction potentials of ferredoxin-nadp+ reductase and flavodoxin from anabaena pcc 7119 and their electrostatic and covalent complexes. | the oxidation-reduction potentials of ferredoxin-nadp+ reductase and flavodoxin from the cyanobacterium anabaena pcc 7119 were determined by potentiometry. the potentials at ph 7 for the oxidized flavodoxin/flavodoxin semiquinone couple (e2) and the flavodoxin semiquinone/hydroquinone couple (e1) were -212 mv and -436 mv, respectively. e1 was independent of ph above about ph 7, but changed by approximately -60 mv/ph below about ph 6, suggesting that the fully reduced protein has a redox-linked p ... | 1991 | 1765067 |
| amplification, cloning, and sequencing of a nifh segment from aquatic microorganisms and natural communities. | by use of the polymerase chain reaction and degenerate oligonucleotide primers for highly conserved regions of nifh, a segment of nifh dna was amplified from several aquatic microorganisms, including an n2-fixing bacterium closely associated with the marine filamentous cyanobacterium trichodesmium sp., a heterotrophic isolate from the root/rhizome of the seagrass ruppia maritima, and the heterocystous freshwater cyanobacterium anabaena oscillarioides. nifh segments were amplified directly from d ... | 1991 | 1768139 |
| antibodies to the n-terminal sequence of gvpa bind to the ends of gas vesicles. | antibodies were raised against intact gas vesicles of anabaena flos-aquae, and against a synthetic peptide (gvpant) whose sequence is identical to the n-terminal region of the main gas vesicle protein, gvpa. a two-stage centrifugation procedure is described for separating gold-labelled antibodies bound to gas vesicles from unbound antibodies. the gvpant antibody bound to gas vesicles that had been previously rinsed with sds to remove the outer gas vesicle protein, gvpc. treatment with this antib ... | 1991 | 1770354 |
| anatoxin-a(s), a naturally occurring organophosphate, is an irreversible active site-directed inhibitor of acetylcholinesterase (ec 3.1.1.7). | anatoxin-a(s) is a guanidine methyl phosphate ester (unprotonated molecular ion equals 252 daltons) isolated from the freshwater cyanobacterium (blue-green alga) anabaena flos-aquae strain nrc 525-17. previous work has shown anatoxin-a(s) to be a potent irreversible inhibitor of electric eel acetylcholinesterase (ec 3.1.1.7, ache). in the present study the interaction of anatoxin-a(s) with ache was investigated by protection studies and since similarities have been noted between anatoxin-a(s) an ... | 1991 | 1770503 |
| inhibitory effect of petroleum oil on photosynthetic electron transport system in the cyanobacterium anabaena doliolum. | 1991 | 1786460 | |
| [pileate mushrooms and algae--objects of cosmic biology]. | 1991 | 1792222 | |
| microcystins from anabaena flos-aquae nrc 525-17. | anabaena flos-aquae nrc 525-17 produces a very potent neurotoxin, anatoxin-a(s). during isolation of the neurotoxin, we found that the strain contains four other toxic compounds which show strong hepatotoxicity. the four toxins, toxins 1, 1', 2, and 3, were successfully purified. toxin 2, one of major toxins, was identified as 3-desmethylmicrocystin lr (1) by comparison of spectral data of the known compound. since the three other toxins contain an unknown amino acid, gc/ms was applied and it re ... | 1991 | 1793802 |
| [investigations of the immunomodulatory effect of cyanobacterial extracts]. | resulting from the knowledge that cyanobacteria (blue-green algae) are able to produce pharmacologically active substances the aqueous extracts from several cyanobacteria species and strains (microcystis aeruginosa, synechocystis aquatilis, oscillatoria redekei, anabaena flos-aque, aphanizomenon flos-aquae, oscillatoria rubescens, oscillatoria tenuis) were tested for their immunomodulating activity. extracts from oscillatoria redekei 051, oscillatoria tenuis 01 and synechocystis aquatilis 428 ca ... | 1991 | 1801597 |
| effects of dimethoate on n2-fixing cyanobacterium anabaena pcc 7119. | 1991 | 1813092 | |
| variation of geosmin content in anabaena cells and its relation to nitrogen utilization. | the addition of the proper amount of ammonium to the culture medium containing nitrate as nitrogen source enhanced the growth rate of anabaena viguieri. the amount of geosmin produced by these cells varied with the concentrations of ammonium added. a negative correlation between the amount of geosmin produced and of the growth rate of cells was revealed. this was also found in cells grown on various forms of nitrogen sources. without supply of any nitrogen compound, this organism is capable of f ... | 1991 | 1814277 |
| the atp1 and atp2 operons of the cyanobacterium synechocystis sp. pcc 6803. | the two operons atp1 and atp2, encoding the subunits of the f0f1 atp-synthase, have been cloned and sequenced from the cyanobacterium synechocystis sp. pcc 6803. the organization of the different genes in the operons have been found to resemble that of the cyanobacteria synechococcus sp. pcc 6301 and anabaena sp. pcc 7120. the synechocystis f0f1 atp-synthase has nine subunits. a tenth open reading frame with unknown function was detected at the 5' end of atp1, coding for a putative gene product ... | 1991 | 1832989 |
| characterization of a gene controlling heterocyst differentiation in the cyanobacterium anabaena 7120. | anabaena 7120 mutant 216 fails to differentiate heterocyst. we previously identified a 2.4-kb wild-type dna fragment able to complement this mutant. we show here that the sequence of this fragment contains a single open reading frame (hetr), encoding a 299-amino-acid protein. conjugation of deletion subclones of this fragment into strain 216 showed that the hetr-coding region is both necessary and sufficient for complementation of the het- phenotype. the mutation in 216 is located at nucleotide ... | 1991 | 1840555 |
| genetic analysis of cyanobacterial development. | filamentous cyanobacteria, the only prokaryotes that form linear patterns of differentiated cells, can be genetically manipulated by the conjugative transfer of plasmids from escherichia coli. it has become possible to determine the cellular localization of genetic transcription, including transcription of developmentally critical genes before morphological differentiation takes place, by using luciferase as a reporter. these techniques are facilitating developmental analysis. | 1991 | 1840890 |
| calcium-dependent protease of the cyanobacterium anabaena: molecular cloning and expression of the gene in escherichia coli, sequencing and site-directed mutagenesis. | it has been suggested that a calcium-dependent intracellular protease of the cyanobacterium, anabaena sp., participates in the differentiation of heterocysts, cells that are specialized for fixation of n2. clones of the structural gene (designated prca) for this protease from anabaena variabilis strain atcc 29413 and anabaena sp. strain pcc 7120 were identified via their expression in escherichia coli. the prca gene from a. variabilis was sequenced. the genes of both strains, mutated by insertio ... | 1991 | 1900347 |
| isolation and complementation of nitrogen fixation mutants of the cyanobacterium anabaena sp. strain pcc 7120. | approximately 140 mutants of anabaena sp. strain pcc 7120 unable to grow aerobically on media lacking fixed nitrogen (fix-) were isolated after mutagenesis with diethyl sulfate and penicillin enrichment. a large cosmid library of wild-type anabaena sp. strain pcc 7120 dna was constructed in a mini-rk-2 shuttle vector, and seven mutants representing several morphologically abnormal heterocyst phenotypes were complemented. one of these mutants, 216, failed to differentiate heterocysts. all of thes ... | 1991 | 1900504 |
| crystals of anabaena pcc 7119 ferredoxin-nadp+ reductase. | crystals of ferredoxin-nadp+ reductase (fnr) from the cyanobacterium anabaena pcc 7119 are grown in the presence of polyethylene glycol 6000 and beta-octyl glucoside. they belong to the hexagonal system. the cell parameters are a = b = 87.8 a, c = 92.7 a, space group p6(1) or p6(5), and a vm of 3.0 a3/dalton for one molecule of 36,000 daltons per asymmetric unit. these crystals diffract strongly up to 1.9 a and are suitable for x-ray structural studies. | 1991 | 1901362 |
| light-dependent de-activation/re-activation of anabaena variabilis ferredoxin: nadp+ reductase. | the activity of ferredoxin: nadp+ reductase (fnr) was found to decline to approximately 20% maximal levels with little or no loss in enzyme levels when cultures of the cyanobacterium anabaena variabilis were maintained in the stationary phase of growth. re-activation of enzyme activity occurred when cells were diluted into either fresh or re-utilized media and illuminated. this reversible de-activation/re-activation process was found, in vivo, to be dependent on the intensity of light illuminati ... | 1991 | 1901489 |